1. module express-graphql
   1. function express-graphql (options)
   2. function express-graphql.getGraphQLParams (request)

module express-graphql

function express-graphql (options)

• description and source-code

  function graphqlHTTP(options) {
    if (!options) {
      throw new Error('GraphQL middleware requires options.');
    }
  
    return function (request, response) {
      // Higher scoped variables are referred to at various stages in the
      // asynchronous state machine below.
      var schema = void 0;
      var context = void 0;
      var rootValue = void 0;
      var pretty = void 0;
      var graphiql = void 0;
      var formatErrorFn = void 0;
      var extensionsFn = void 0;
      var showGraphiQL = void 0;
      var query = void 0;
      var documentAST = void 0;
      var variables = void 0;
      var operationName = void 0;
      var validationRules = void 0;
  
      // Promises are used as a mechanism for capturing any thrown errors during
      // the asynchronous process below.
  
      // Resolve the Options to get OptionsData.
      return new Promise(function (resolve) {
        resolve(typeof options === 'function' ? options(request, response) : options);
      }).then(function (optionsData) {
        // Assert that optionsData is in fact an Object.
        if (!optionsData || (typeof optionsData === 'undefined' ? 'undefined' : _typeof(optionsData)) !== 'object') {
          throw new Error('GraphQL middleware option function must return an options object ' + 'or a promise which will be resolved
   to an options object.');
        }
  
        // Assert that schema is required.
        if (!optionsData.schema) {
          throw new Error('GraphQL middleware options must contain a schema.');
        }
  
        // Collect information from the options data object.
        schema = optionsData.schema;
        context = optionsData.context || request;
        rootValue = optionsData.rootValue;
        pretty = optionsData.pretty;
        graphiql = optionsData.graphiql;
        formatErrorFn = optionsData.formatError;
        extensionsFn = optionsData.extensions;
  
        validationRules = _graphql.specifiedRules;
        if (optionsData.validationRules) {
          validationRules = validationRules.concat(optionsData.validationRules);
        }
  
        // GraphQL HTTP only supports GET and POST methods.
        if (request.method !== 'GET' && request.method !== 'POST') {
          response.setHeader('Allow', 'GET, POST');
          throw (0, _httpErrors2.default)(405, 'GraphQL only supports GET and POST requests.');
        }
  
        // Parse the Request to get GraphQL request parameters.
        return getGraphQLParams(request);
      }).then(function (params) {
        // Get GraphQL params from the request and POST body data.
        query = params.query;
        variables = params.variables;
        operationName = params.operationName;
        showGraphiQL = graphiql && canDisplayGraphiQL(request, params);
  
        // If there is no query, but GraphiQL will be displayed, do not produce
        // a result, otherwise return a 400: Bad Request.
        if (!query) {
          if (showGraphiQL) {
            return null;
          }
          throw (0, _httpErrors2.default)(400, 'Must provide query string.');
        }
  
        // GraphQL source.
        var source = new _graphql.Source(query, 'GraphQL request');
  
        // Parse source to AST, reporting any syntax error.
        try {
          documentAST = (0, _graphql.parse)(source);
        } catch (syntaxError) {
          // Return 400: Bad Request if any syntax errors errors exist.
          response.statusCode = 400;
          return { errors: [syntaxError] };
        }
  
        // Validate AST, reporting any errors.
        var validationErrors = (0, _graphql.validate)(schema, documentAST, validationRules);
        if (validationErrors.length > 0) {
          // Return 400: Bad Request if any validation errors exist.
          response.statusCode = 400;
          return { errors: validationErrors };
        }
  
        // Only query operations are allowed on GET requests.
        if (request.method === 'GET') {
          // Determine if this GET request will perform a non-query.
          var operationAST = (0, _graphql.getOperationAST)(documentAST, operationName);
          if (operationAST && operationAST.operation !== 'query') {
            // If GraphiQL can be shown, do not perform this query, but
            // provide ...

• example usage

  n/a

function express-graphql.getGraphQLParams (request)

• description and source-code

  function getGraphQLParams(request) {
    return (0, _parseBody.parseBody)(request).then(function (bodyData) {
      var urlData = request.url && _url2.default.parse(request.url, true).query || {};
      return parseGraphQLParams(urlData, bodyData);
    });
  }

• example usage

  ...
  Given an HTTP Request, this returns a Promise for the parameters relevant to
  running a GraphQL request. This function is used internally to handle the
  incoming request, you may use it directly for building other similar services.
  
  ```js
  const graphqlHTTP = require('express-graphql');
  
  graphqlHTTP.getGraphQLParams(request).then(params => {
    // do something...
  })
  ```
  
  
  ## Debugging Tips
  ...